• Journal of Biomedical Engineering Research
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• v.15 no.2
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• pp.195-200
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• 1994

To develop an artificial bone substitute that is gradually degraded and replaced by the regenerated natural bone, the authors designed a composite that consists consisted of calcium phosphate and collagen according to the natural bone's main composition. The crystallinity of the synthesized apatite was shown to depend on the synthesis temperature. Carbonate apatite synthesized at $58{\circ}C$ demonstrated crystallinity very similar to that of the natural bone. By sintering the apatite over $700{\circ}C$ in vacuum, porous carbonate apatite could be obtained, and the pore extent was controllable according to the additive hydrogenperoxide volume.

• Journal of the Korean institute of surface engineering
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• v.37 no.5
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• pp.243-248
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• 2004

A palladium-nikel(Pd-Ni) alloy composite membrane has been fabricated on microporous nickel support formed with nickel powder. Plasma surface treatment process is introduced as pre-treatment process instead of HCI activation. Pd coating layer was prepared by dc magnetron sputtering deposition after $H_2$ plasma surface treatment. Palladium-nickel alloy composite layer had a fairly uniform and dense surface morphology. The membrane was characterized by permeation experiments with hydrogen and nitrogen gases at temperature of 773 K and pressure of 2.2psi. The hydrogen permeance was 6 ml/minㆍ$\textrm{cm}^2$ㆍatm and the selectivity was 120 for hydrogen/nitrogen($H_2$/$N_2$) mixing gases at 773 K.

• Advances in nano research
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• v.13 no.3
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• pp.247-257
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• 2022

Extraordinary properties of nanocomposites make them a primary replacement for many conventional materials. Anterior cruciate ligament (ACL) reconstruction, which is a frequent surgery in sport activities, is one of the fields in which nanocomposites could be utilized. In the present study, the mechanical properties of different porous scaffolds made from graphene nano-composites are presented ad load bearing capacity of these materials is calculated using finite element method. The numerical results are further compared with experimental published data. In addition, several geometrical and material parameters are analyzed to find the best configuration of nanocomposite scaffolds in reconstruction of ACL. Moreover, coating of detoxification chemicals are extremely easier on the nano-structured materials than conventional one. Detoxification potential of nano-composites in the injured body are also discussed in detail. The results indicated that nano-composite could be successfully used in place of auto- and allografts and also instead of conventional metallic screws in reconstruction of ACL.

• Membrane Journal
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• v.22 no.3
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• pp.191-200
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• 2012

New composite membranes were manufactured by impregnating post-sulfonated poly(arylene ether sulfone)s containing perfluorocyclobutane (PFCB) groups into porous polytetrafluoroethylene (PTFE) films. Two kinds of post-sulfonated poly(arylene ether sulfone)s with two different monomer ratios (sulfonable biphenylene monomer : non-sulfonable sulfonyl monomer = 6 : 4, 4 : 6) were first prepared through three synthetic steps: synthesis of trifluorovinylether-terminated monomers, thermal cycloaddition polymerization and post-sulfonation using chlorosulfonic acid (CSA). The composite membranes were then prepared by adjusting the concentrations (5~20 wt%) of the resulting copolymers impregnated in the PTFE films. The water uptake, ion exchange capacity (IEC) and ion conductivity of the composite membranes were characterized and compared with their unreinforced dense membranes and Nafion. All the synthesized compounds, monomers and polymers were characterized by $^1H$-NMR, $^{19}F$-NMR and FT-IR and the composite membranes were observed with scanning electron micrographs (SEM).

• Fire Science and Engineering
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• v.26 no.4
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• pp.42-47
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• 2012

In the study, fire extinguishing concentration of $K_2CO_3$-Zeolite composite was measured. Zeolite composite is a porous adsorbent which has small particle size, low density and anti-catalytic effect. Scanning Electron Microscopy, X-Ray diffraction and thermal analysis were also conducted to investigate the structural properties of composite. The result showed that despite of weight ratio, the extinguishing concentration of the composite was lower than pure $K_2CO_3$. The extinguishing concentration of $K_2CO_3$-Zeolite composite which has weight ratio of 7 : 3 was 5.72 times lower than that of pure $K_2CO_3$ and 1.1 times lower than that of ABC powder. The SEM and XRD patterns showed that $K_2CO_3$ was adsorbed on the Zeolite properly, and through the thermal analysis, it was founded that the composite is more effective extinguishing agent than pure $K_2CO_3$.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.5
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• pp.157-164
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• 2021

Recently, a number of studies have been conducted on photocatalysts and adsorbents that can remove harmful substances to improve environmental problems related to fine particles. In this study, a porous foam composites were fabricated using palm-based activated carbon having a large amount of micro-pores and foam concrete with a significantly larger total pore volume compared to general construction materials. To evaluate the adsorption potential of fine particles, the pore structure of the foam composites were analyzed. For the analysis of the pore structure of the foam composite, BET and Harkins-jura theory were applied from the measured nitrogen adsorption isotherm. From the results of the analysis, the specific surface area and micro-pore volume of the foam composite containing activated carbon increased significantly compared to Plain. As thereplacement of activated carbon increased, the specific surface area and micro-pore volume of the foam composite tended to increase. It seems that the foam composite has high adsorption performance for gaseous fine particle precursor such as nitrogen oxides.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1821-1823
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• 1999

Carbon is an attractive material on electro double capacitor which depend on charge storage in the electrode/electrolyte interfacial double layer. Carbonaceous material for double layer capacitor can be obtained from carbon powder, fiber, film and porous carbon sheet. The capacitance of electrodes using an activated carbon was influenced by a filling density of the carbon, thickness and internal resistance of the electrode. In this study. to reduce internal resistance and increase electric conductivity of the electrode. activated carbon/carbon(AC/C) composite electrode was fabricated. The capacitors which have energy densities of 68F/g(at $30^{\circ}C$), 109F/g(at $60^{\circ}C$) and $68F/cm^3$(at $30^{\circ}C$), $111F/cm^3$(at $60^{\circ}C$) were fabricated by using AC/C composite electrodes.

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1659-1664
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• 2014

A porous metal-organic framework (MOF), MIL-101, was synthesized in the presence of sulfated zirconia (SZ) to produce acidic SZ/MIL-101 composites for the first time. The composites were characterized with XRD, nitrogen adsorption, FT-IR, scanning electron microscope, chemical analysis and so on. The composites (SZ/MIL-101s) were successfully applied in a liquid-phase esterification for a high yield of ester. This catalytic result of SZ/MIL-101, compared with that of pure SZ or MIL-101 (showing a negligible yield of ester), suggests that the SZ in the composite is highly active in the acid catalysis probably because of the well-dispersed active species of SZ. Moreover, the esterification is catalyzed in heterogeneous mode as confirmed by negligible esterification after filtration of the catalyst. Finally, microwaves can be efficiently applied both in the synthesis of the composites and the esterification reaction to accelerate the two processes of synthesis and esterification by about 5 times.

• Journal of Electrochemical Science and Technology
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• v.2 no.2
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• pp.124-129
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• 2011

A simple process of fabricating micropillar structure and its influence upon enhancing electrochemical biosensor response were studied in this work. Conducting polymer PEDOT was used as a base material in formulating a composite with PVA. Micro porous PC membrane filter was used as a template for the micropillar of the composite on ITO electrode. This structure could provide plenty of encapsulating space for enzyme species. After dosing enzyme solution into this space, Nafion film tent was cast over the pillar structure to complete the micropillar cavity structure. In this way, the encapsulation of enzyme could be accomplished without any chemical modification. The amount of enzyme species was easily controllable by varying the concentration of the dosing solution. The more amount of enzyme is stored in the sensor, the higher the electrochemical response is produced. One more reason for the sensitivity improvement comes from the large surface area of the micropillar structure. Application of 0.7 V produced the best current response under the condition of pH 7.4. This biosensor showed linear response to the glucose in 0.1~1 mM range with the average sensitivity of $14.06{\mu}A/mMcm^2$. Detection limit was 0.01 mM based on S/N = 3.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.87-90
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• 2003

In Resin transfer molding (RTM), composite parts are produced by impregnation of a dry reinforcement with liquid matrix resin. Permeability is a key issue in this process. For thin parts, the resin flow in the thickness direction can be neglected. Therefore thin parts are considered as two-dimensional composites. However the resin flow through the thickness is important to thicker parts and we have to consider out-of-plane permeability. This work discusses a method to measure out-of-plane permeability. The flow rate and pressure drop across the porous media were measured. Also one dimensional form of Darcy's law is applied to calculate the out-of-plane permeability of various preforms. The flow is injected uniformly into layers of the preform. And a circular fiber mat with 6cm diameter was cut and flattened from cylindrical mandrel.